I like to think that I am the master of my thoughts—that I generate and control them and that they serve my own purposes. But that is only one way to look at things.

It has been said that if alien scientists landed on earth they might report home that wheat, corn and rice were the master species, living comfortably on almost 600 million hectares of land, their every need tended by human servants. These grasses have enticed humans to spread their seed far and wide after preparing the most favorable soil conditions. The human servants provide extra nutrients and water when these are in short supply, fend off pests, and finally harvest and store seed, receiving a portion of the plants’ productive capacity as compensation for their faithful service—only to repeat the cycle during the next growing season.

Our relationship to ideas, too, seems very different when we flip the story around. Like corn and wheat, ideas help us survive, but one might also say that the opposite is true.

Ideas have a life of their own. Just as planet earth is host to millions of species in an intricate web that we call the biosphere, it is possible to think of an ideosphere a web of ideas as intricate and diverse as the web of life. These ideas evolve and reproduce not on a planet, but in the fertile world of conscious minds. Much like living organisms, they can be thought of as discrete entities, as self-replicators that have an existence all their own.

No analogy fits perfectly, but when it comes to the relationship between us, as human hosts, and our ideas, it may easiest to compare ideas to microbes, specifically those that live on or in other organisms. Like the microbes we carry around, ideas are contagious—some more than others. They get transmitted from one person to another through our contacts and communities. Scholars can trace the spread of a contagious idea—a new slang word like “woke” or a fashion fad like saggy pants the way that epidemiologists trace the spread of a disease.

Also like micro-organisms, ideas are subject to natural selection—pressures that cause them to flourish or evolve or to die out altogether independent of whether some of their hosts—meaning us—live or die.

In his book, The Selfish Gene, Richard Dawkins coined the term meme to describe a unit of information that can get passed from person to person (host to host), evolving over time. Dawkins and other scientists of his generation had come to recognize that natural selection operates on a variety of media, not just DNA. In fact, it can operate on any medium in which information has the opportunity to replicate and mutate and then get passed on or not—including the internet (think computer viruses) or the interconnected network of human minds.

In Dawkins’ framework, individual religious dogmas can be thought of as memes, while whole religious ideologies, which comprise sets of ideas that are bound together and tend to travel in tandem are called meme complexes. Academic psychologist and biologist Susan Blackmore has built on Dawkins’ work to further clarify what memes are and how they function.

The phrase that Dawkins used in his title, the selfish gene, refers to the fact that—to put it in wildly anthropomorphic terms—a gene doesn’t give a damn if you survive, so long as it does. From an evolutionary standpoint, it’s fine for the male black widow to get eaten after mating, because that helps his genes get passed on. By analogy, a viral idea or ideology may kill its human host (think Jihadis and martyrdom) so long as that helps it, in this case radical Islam, to spread.

Contagious ideas, like the idea of 72 virgins awaiting a Muslim martyr, may be selfish memes. They may be indifferent to our survival, but we are not. Your average Jihadi might think twice about suicide if he suspected those promised virgins were actually raisins (a less viral translation of the Arabic passage)—or worse, if he suspected the Christian version of the afterlife might be the real one.

Whether in this life or some anticipated afterlife, each of us wants to maximize our own pleasure and wellbeing and that of people we love—and to do that we must know what is real. That’s why we have evolved sophisticated mental defenses that detect and correct misinformation. Our finely-tuned bullshit detectors react to false ideas in much the same way that our immune system reacts to parasitic bacteria, viruses, prions, and fungi that have adapted to live in and on our bodies—by identifying potential harms and eliminating them.

But as we all know, immune systems are far from perfect. Pathogens evolve a variety of successful strategies to get around human immune defenses and then trigger us to do things that pass on their genes to other people—sneeze, for example. Some pathogens—like influenza—mutate rapidly, so that old antibodies won’t work. Others, like Herpes Simplex hide in places our immune system can’t reach and then emerge from time to time to get spread. Still others, like MRSA, develop into mutant “superbugs” capable of withstanding treatments that would have wiped out their ancestors. In his 2001 book, Parasite Rex, Carl Zimmer described the fascinating arms race between biological hosts and parasitic organisms.

Like our biological immune systems, our psychological immune systems—what I called bullshit detectors—are far from perfect. And like microbes, false but viral ideas have a variety of successful strategies for getting passed on. They may seem so intuitively reasonable or so impressively complex that we defer when our authority figures spout them. They may elicit an appealing sense of clarity or an addictive sense of outrage. They may mimic other concepts that are indisputably real: I have a biological father, why not a father in heaven?

Some memes, like chain mail or Christianity, even have an explicit “copy me” command. If you care at all about people with cancer, hit share! – or – Go into the world and make disciples of every creature.

So, let’s put this all together: As viral self-replicators, ideas have a life of their own. Human beings have a cognitive immune system that seeks to identify and eradicate false ideas because misinformation tends to cause us trouble. Some false ideas evade our bullshit detectors and so get passed socially from person to person. In this context, when religious notions take root in human minds and get passed on despite containing maladaptive falsehoods that do us harm, they may be considered socially transmitted pathologies or, to use my earlier term, socio-pathologies.

But there is a catch. Did you notice all those qualifiers?

Part 3 in a 4-part series. Read Part 4 here. This series was abridged as a single article in The Humanist – A magazine of critical inquiry and social concern. May/June 2017 issue, p. 16-21.